The present invention relates to vehicles roof and a method and apparatus to adjust the light exposure of the skin through the vehicle roof.
The present invention relates to an adjustable ultraviolet transmission vehicle sunroof with translational elements to transmit, partially transmit, or block solar ultraviolet radiation. This allows persons in the vehicle to obtain additional potentially beneficial ultraviolet exposure in the fall and winter or other times when a deficiency in exposure is common. It also allows persons in the vehicle to protect themselves from possibly harmful ultraviolet radiation in the spring and summer or other times when overexposure is common. The exposure can be adjusted according to the skin type and needs of the individuals in the vehicle.
Convertibles provide good visibility, enjoyable exposure to sunlight, fresh air and a feeling of spaciousness. However, the hazard in accidents has led to a variety of modifications including Increasingly popular sunroofs. The nearly universal use of vehicle air conditioners has resulted in many persons having the windows closed not only when it is cold in the winter but also when it is warm or hot in the summer. Since the windows block the biologically active ultraviolet radiation, persons with a deficiency in exposure miss a possibly beneficial exposure especially in the fall and winter when an underexposure is common. Some have proposed the use of ultraviolet transmitting glazing to obtain full spectrum solar radiation exposure. However, there is an associated potential hazard of increasing the risk of sunburn and skin cancer, especially for light skin persons living in bright areas such as Australia.
An open sunroof with direct exposure to sunlight is an obvious hazard. The hazard of sunlight is so well publicized some may be over reacting and not obtaining sufficient sunlight as discussed by Ness and debated by many. The ultraviolet protection afforded by common glass is recognized by most persons. The use of ultraviolet glazing for vehicles as proposed by Wendel and Downing requires great care to avoid potential hazards. Light and dark skin persons have greatly different tolerances and needs.
The ultraviolet transmitting glass looks just like glass that blocks the ultraviolet radiation so the hazard is hidden. Skin cancer in animals can be produced by suberythemal daily doses. One would expect humans likewise may develop skin cancer by a series of daily doses none of which cause a noticeable reddening of the skin. The skin cancer may occur long after the exposure. In addition, a large dose of vitamin D significantly reduces depression and improves the mood, Gloth. Thus sunlight induced vitamin D is reasonably expected to reduce depress,ion and improve the mood just as is generally experienced in the spring.
The combination of hidden hazard, delayed occurrence of effects and increased feeling of well being make great care necessary in the initiation of the use of ultraviolet transmitting glazing for vehicles. Precautions such as government regulations requiring a slight noticeable unique color tint or other distinguishing easily-noticeable feature for ultraviolet transmitting glazing may be expected.
There are many difficulties in initiating the use of ultraviolet transmitting glazing. However, as pointed out by Ness there is some possibility of reductions in the extent of diseases such as coronary heart disease and some types of cancer. Darker areas tend to have higher incidences of these diseases. Thus the time of the year to increase exposure is when underexposure is common, the fall and winter. Fortunately, the time of year when overexposure is common is the rest of the year. Using ultraviolet transmitting glazing during the dark part of the year and ultraviolet blocking or partially blocking glazing during the rest of the year is a reasonable approach. There is a possibility of both obtaining the benefits of an additional light exposure and avoiding an increased risk of sunburn and skin cancer.
Some prior art includes the proposed use of ultraviolet transmitting glazing. The use of full spectrum transmission to wavelengths as short as 280 nm is sometimes listed including references to Professor Hollwich. Professor Hollwich proposes the solar spectrum is best and through the eyes light maintains a proper hormone and metabolic balance. In a recent publication he described how removal of cataracts (which were blocking sufficient irradiation of the retina) restored proper metabolic balance. Since the skin responds to wavelengths near 290 nm while these wavelengths are filtered out before reaching the retina, full spectrum irradiation for health includes both effects of skin exposure at short wavelengths and through-the-eyes exposure of the retina for longer wavelengths.
The full spectrum theory that natural sunlight is best can be oversimplified in application in some subtle ways. For example, migration has resulted in persons living in areas not well suited for their skin type. Whites with countries of origin of their ancestors in northern latitudes are living in bright areas such as Australia. Blacks with countries of origin of their ancestors near the equator are living in areas with little sunlight in the winter.
The solar radiation environments near the equator as compared with the environments at higher latitude have several differences. Near the equator the length of the day doesn""t change much throughout the year. At noon the sun is relatively high in the sky. In contrast at higher latitudes the length of the day is short in the winter, long in the summer and the sun is not very high in the sky in winter at noon.
The equatorial clear day visible light is not greatly different than that in the summer at higher latitudes. The sun is relatively high in the sky near noon during the summer over a relatively large range it latitudes. The visible attenuation doesn""t change greatly with sun elevation. For ultraviolet radiation the attenuation by the atmosphere is much greater than for visible light. At high latitudes the ultraviolet radiation varies greatly with the season and latitude. Near the equator the clear day ultraviolet radiation is high and doesn""t change much with season (WHO-160, listed in references).
The overall effect is blacks have a skin adapted for a relatively constant and high level ultraviolet environment. Whites have a skin""suitable for very low ultraviolet radiation in the winter. Some whites have little capability for tanning for protection in the summer while others tan and bleach effectively.
Blacks at high latitudes generally have a large deficiency in ultraviolet exposure in the winter. Whites at low latitudes generally have a large ultraviolet overexposure during the summer. This applies not only to the skin but also to the eyes. Blacks usually have dark highly attenuating eyes. Many whites have light-colored low attenuating eyes.
Thus when controlling the light environment just providing full spectrum transmission or lighting can be an oversimplification. Adjusting the visible and ultraviolet environment depends on the time of year and an individuals skin type. It also depends on the occupation and skin exposure habits. An office worker usually has greater needs for additional light than an outdoor worker. A person with gardening or outdoor sports as a hobby usually has less need for supplemental exposure.
The skin exposure of an individual needs to be controlled with the objective of both avoiding overexposure (decreasing the risk of sunburn and skin cancer) and obtaining sufficient exposure during the rest of the year to increase the probability for good health. Full spectrum transmission is an oversimplification and needs to be modified depending on a persons skin type, sun exposure habits and the local environment.